Cestodes (tapeworm) Flashcards
Multicellular organisms, elongated and bilaterally symmetric
Helminths Characteristics
Tegument
Protective covering or cuticle (smooth rigid, spines or tubercles)
Protective covering or cuticle (smooth rigid, spines or tubercles)
Tegument
Attachment structures
Hookers, sucker, teeth, plates
Primitive nervous and excretory systems
Alimentary canal in some
No circulatory system
Helminths characteristics
Cestodes…AKA…
Tapeworms
Segments called ___ form the body
Proglottids
chain of proglittids
Strobila
(head)- differ in number and placement of suckers and presence or absence of hooklets
Scolex
pointed end of scolex that has points of attachments (suckers, hooklets, etc.)
Rostellum
Hermaphroditic
Lack digestive systems
Nutrition absorbed through body walls
Cestodes
six-hooked larval form released when egg hatches
Oncosphere
Most eggs are nonoperculated and contain hexacanth embryo (six-hooked)
Cestode eggs
Taenia Saginata
Beef tapeworm
Oncospheres develp into ____ in muscle
Cysticerci
T. saginata vs T. solium which is bigger
T. Saginata (beef)
___ ___ persists in the U.S through the consumption of rare steak.
Taenia saginata
___ ___ is more prevalent in poorer communities where humans live in close contact with pigs and eat undercooked pork.
Taenia Solium
___ ___ is limited to Asia and is seen mostly in the Republic of Korea, China, Taiwan, Indonesia, and Thailand.
Taenia asiatica
Mild abdominal symptoms
Most striking feature consists of the passage (active and passive) of proglottids
Occasionally, appendicitis or cholangitis can result from migrating proglottids.
Taenia Saginata taeniasis
Less frequently symptomatic than Taenia saginata taeniasis.
Main symptom is the passage (passive) of proglottids.
Most important feature of ___ ___ ___ is the risk of development of cysticercosis.
Taenia Solium taeniasis
Microscopic identification of eggs and proglottids in feces is diagnostic for taeniasis, but is not possible during the first 3 months following infection, prior to development of adult tapeworms.
TAenia Saginata
Repeated examination and concentration techniques will increase the likelihood of detecting light infections. Nevertheless, identification of Taenia sp. is not possible if solely based on microscopic examination of eggs.
Taenia Saginata
Most important feature of Taenia solium taeniasis is the risk of development of _____
Cysticercosis.
Four, muscular cup-shaped suckers
No crown of hooklets on rostellum
Taenia Saginata
Tapeworm acquired through eating larvae in under cooked beef.
Adults in small intestine.
T. Saginata
Scolex has 4 suckers and no hooks.
Taenia saginata
Gravid proglottid is longer than wide and has 15-30 lateral uterine branches.
Taenia saginata
Symptoms: rare with vague abdominal discomfort or indigestion.
Taenia saginata
infection of both humans and pigs with larval stages of Taenia solium
T. Solium
Cysticercosis
T. solium:
Humans are infected either by ingestion of food contaminated with feces, or by ____
Autoinfection
in _____ a human infected with adult T. solium can ingest eggs produced by that tapeworm, either through fecal contamination or, possibly, from proglottids carried into the stomach by reverse peristalsis
Autoinfection
T. solium:
Extracerebral cysticercosis can cause ____, cardiac, or spinal lesions with associated symptoms
Ocular
T. Solium:
Of greatest concern is cerebral cysticercosis (or neurocysticercosis), which can cause diverse manifestations including ____, mental disturbances, focal neurologic deficits, and signs of space-occupying intracerebral lesions. Death can occur suddenly
Seizures
Demonstration of Taenia solium eggs and proglottids in the feces diagnoses ____ and not cysticercosis.
Taeniasis
Scolex
Four, muscular cup-shaped suckers
Crown of hooklets
Taenia solium
Persons who are found to have eggs or proglottids in their feces should be evaluated serologically since autoinfection, resulting in ____, can occur.
Cysticercosis
Count the number of primary uterine branches to determine the species
__ __: 7-13
T. Solium
Presence of ____:
Appearance of calcified cysticerci in soft-tissue x-rays
Surgical removal of subcutaneous nodules
Cysts in eye
CNS lesions can be detected with CT (computed tomography)
Cysticerci
Acquire the adult tapeworm in the small intestine by eating undercooked pork (taeniasis).
T. Solium
Acquire the larvae by eating tapeworm eggs (cysticercosis).
T. Solium
Scolex has 4 suckers and hooks.
T. Solium
Gravid proglottids are longer than wide and have less than 14 uterine branches.
T. Solium
Symptoms: mild with possible epigastric fullness. Cysticercosis symptoms vary by tissue, but 60% encyst in the brain, 3% in the eye for more noticeable visual symptoms and seizures. Calcified cysts may be seen in x-rays or scans
T. Solium
Distribution is worldwide in pork eating countries.
T. Solium
“Fish” or “Broad tapeworm”
Diphyllobothrium latum
Largest human tapeworm (up to 10m long)
Diphyllobothrium latum
Adult tapeworm in small intestine is acquired by eating undercooked freshwater fish that contain the pleurocercoid larvae
D. latum
Has two intermediate hosts, copepod and fish
D. latum
Scolex has bothria and no hooks
D. latum
Proglottids have a central uterine “rosette”
D. latum
Eggs operculated
D. latum
Symptoms: often none unless proglottids migrate to the gall bladder or bile ducts. Can cause vitamin B12 deficiency.
D. latum
Distribution is countries and cultures that eat undercooked fish
D. latum
Human ____ (hydatidosis, or hydatid disease) is caused by larval stages of cestodes (tapeworms) of genus Echinococcus
Echinococcosis
Echinococcus granulosus causes ____ echinococcosis, the form most frequently encountered
Cystic
E. multilocularis causes ___ echinococcosis
Alveolar
E. vogeli causes ____ echinococcosis
Polysystic
____ is an extremely rare cause of human echinococcosis (3 cases)
E. oligarthrus
Larval worm is acquired by eating parasite eggs from dogs or other canines.
Echinococcus
Forms cysts primarily in liver and then in other organs, the type of cyst and location will determine treatment.
Echinococcus
Symptoms: from mild to severe depending on location and incubation time 5-40 years.
Echinococcus
Diagnosis is with imaging and clinical findings, confirm with EIA
Can be fatal if left untreated, careful surgery is usually involved. Cysts can spread or reoccur.
Eichonococcus
Dwarf tapeworm” 2-4 cm long
Hymenolepis nana
20 million or more infections worldwide, mostly children or institutionalized populations
H. nana
Spread through ingestion of insect IH, eggs, or autoinfection with eggs.
Larvae can develop in human intestine as a “cysticercus”.
H. nana
Mild abdominal discomfort unless heavily infected.
Eggs are diagnostic with polar filaments.
Treatment is single dose of praziquantel 25 mg/kg
H. nana
20-60cm long
Scolex lacks hooklets
Hymenolepis diminuta
Egg
Larger than H. nana
Bile stained
No polar filaments
H. diminuta
Requires larval insects “mealworms” to reach infective cysticercoid stage
Proglottids overlap each other
H. diminuta
___ ___ is most common cause of all cestode infections, and is encountered worldwide.
Hymenolepis Nana
Known as “pumpkin seed” tapeworm due to shape of mature proglottid
25 eggs in packet
Dipylidium caninum
Pets may exhibit behavior to relieve anal pruritis (such as scraping anal region across grass or carpeting).
Dipylidium caninum
Mild gastrointestinal disturbances may occur.
The most striking feature in animals and children consists of the passage of proglottids.
These can be found in the perianal region, in the feces, on diapers, and occasionally on floor covering and furniture
Dipylidium caninum
D. Caninum:
The proglottids are ___ when freshly passed and may be mistaken for maggots or fly larvae
Motile
Adult tapeworm is acquired by accidentally eating an infected flea from a dog or cat.
More common in children.
Dipylidium caninum
Tapeworm resides in small intestine.
Eggs or motile proglottids passed in stool (diagnostic)
Dipylidium caninum
Symptoms are light or asymptomatic, but abdominal pain, diarrhea, and anal pruritis is possible.
Treatment is praziquantel 5-10 mg/kg
Dipylidium caninum
The genus ____ occurs worldwide in distribution, although most human cases of sparganosis are recorded from southeast Asian countries.
Spirometra
____ can produce painful inflammatory tissue reactions and nodules.
Tissue reaction in eye is very painful, and usually causes periorbital edema.
May cause development of corneal ulcers.
Ocular disease is often associated with use of frog or snake flesh as a poultice over a wound near the eye.
Sparganosis
Sparganum is a larvae acquired through eating or drinking an infected copepod, undercooked meat, or tissue exposure (____).
Poultice
Larvae may migrate through the subcutaneous tissue causing inflammation and pain especially periorbitally.
Spirometra sp.
sparganosis
More common in Asian cultures that apply poultices as medicine, rare in U.S Spirometra species are found worldwide.
Spirometra sp.
sparganosis
Symptoms include swelling and pain.
Surgical removal is the best treatment. High dose praziquantel 120-150 mg/kg has shown some effect.
Spirometra sp.
sparganosis
Which of the following structures are characteristic of cestodes?
a. round
b. proglottids
c. eggs are the only d. diagnostic form
operculated eggs
b. proglottids
A 50 year old man returning from a two year stay in Latin America is complaining of migraines with fever and myalgia. Exam looks fine except for elevated phosphokinase and mild eosinophilia. Lab results are unremarkable with multiple negative O & P exams. Cerebral MRI shows intraventricular cysts with perilesional focal edema. With what is this person infected? a. Hymenolepis nana b. Echinococcus vogeli c. Yersina pestis d. Taenia solium
b. Echinococcus vogeli
pleurocercoid = ?
Diphyllobothriasis latum
